A wide variety of audio recording and playback devices have been developed. The most popular of these uses a small magnetic tape cassette. Audio information, such as music and speech, can be recorded on the tape and played back in any corresponding playback unit. Many such units have both recording and playback capability. To record these cassettes, the tape is fed past a recording head at a constant standard tape speed, conventionally 17/8 inches per second. The tape can then be played back on any standard speed unit that can feed the tape past a pickup head at that speed.
In addition to their general entertainment value, such tape playback units are of great use in providing information, such as recorded books and the like, to persons who are blind or illiterate. In a particularly advantageous application, the Bible or other appropriate literature can be recorded on tape and provided with a player to church members and prospective converts by churches and missionaries. Many of the new converts are in remote locations, with no literature and no trained pastors. Often these people are illiterate or, though literate, have a preference for hearing rather than reading Scripture.
The use of conventional tape players by these persons has not been fully effective. Conventional tape players are relatively expensive and provide capabilities not necessary for these purposes. Further, the internal components of these players are open when the tape is being changed and they have openings for rotary volume controls and the like. Water, dirt and other contaminants may easily enter and damage the unit. Also, since conventional tape players can play all standard speed tape cassettes, the players may be stolen from a person who only wishes to listen to the spoken Bible and used to play general, usually music, cassettes.
Thus, there is a continuing need for improved audio playback systems for use with recordings of the Bible and similar literature that is sturdy, low cost, entirely enclosed and self-contained, sealed against non-destructive opening and that uses standard tape cassettes while preventing the play of cassettes recorded in the normal manner.